JPH0520936Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control valve that controls the drive of a fluid pressure actuator.

[Prior Art] Conventionally, a valve capable of controlling the opening amount and pressure in a fluid flow path is configured as a simple single structure,
Furthermore, when pressurized fluid is supplied to the target location, it is always supplied through only a single valve seat, minimizing pressure loss.
The one described in Japanese Patent No. 60-126769 is known.

As shown in FIG. 12, the above-mentioned known control valve has the following features:
First and second valve seats 5 and 6 that communicate the first port 2 formed in the main body 1 with the second port 3 and the third port 4 are provided in the main body 1 in a back-to-back state, and these valve seats 5, first and second valve bodies 7, which open and close valves 6 separately;
A piston 1 has a rod 9 slidably inserted into the piston 8 and a piston 1 which is slidably inserted into the main body 1 at one end of the rod 9.
0, and the rod 9 is provided with a locking shoulder 11 that engages with the first valve body 7, and one pressure chamber 12 of a pair of pressure chambers 12 and 13 formed on both sides of the piston 10 is The first port 2 is connected to a first pilot port 14 which opens the other pressure chamber 13 to the outside, and the first valve body 7 is placed in a back chamber 15 defined behind the first valve body 7. A spring 16 that urges the valve seat 5 is compressed, the back chamber 15 is communicated with the first port 2, and a back chamber 17 defined behind the second valve body 8 is opened to the outside. Second
The second valve body 8 is connected to the pilot port 18 .
An adjustment mechanism 19 is attached thereto for regulating the opening displacement amount of the second valve seat 6 and adjusting the opening amount of the second valve seat 6.

In the above known control valve, the first valve seat 5 is connected to the piston 1.
Since the second port 3 is opened and closed by the pressure difference between the pressure chambers 12 and 13 on both sides of the piston 10, the second port 3 is connected to a high pressure fluid source and the first pilot port 14 connected to the pressure chamber 13 on one side of the piston 10 is connected. By applying a pilot pressure such that Further, the opening and closing of the second valve seat 6 is performed by the pressure difference between the first port 2 and the back chamber 17 of the second valve body 8, and the opening displacement amount of the second valve body 8 is controlled by the adjustment mechanism 19. Therefore, the opening amount of the second valve seat 6, that is, the flow rate is adjusted thereby.

Therefore, this control valve has a simple single structure because the first valve seat 5 side functions as a pressure control valve and the second valve seat 6 side functions as a flow rate control valve, and they also function as an on/off valve. It is possible to control the drive of a fluid pressure actuator even though the valve is a small valve.

However, in the known control valve, the second valve body 8 closes the second valve seat 6 due to the second pilot fluid pressure acting on the back chamber 17 of the second valve body.
If the second pilot fluid pressure decreases or is lost for some reason, or if the fluid pressure in the first port 2 increases abnormally, the second valve element 8 opens the second valve seat 6 and the pressure in the first port 2 increases. Pressure fluid is connected to the third port 4
As a result, the fluid pressure actuator connected to the first port 2 will malfunction. This malfunction of the fluid pressure actuator not only has the risk of damaging the actuator, etc., but is also extremely dangerous for the operator, so it is necessary to prevent it. In the event of loss, it is desirable to put the fluid in an emergency stop state (closed center).

Furthermore, since the second valve body 8 is pressed toward the second valve seat 6 by the second pilot pressure that is higher than the fluid pressure in the first port 2, an excessive load is applied to the second valve body 8, resulting in poor durability. There are also some shortcomings.

[Problems to be solved by the invention] The invention provides a control valve that integrally includes a valve having the functions of a pressure control valve and an on-off valve, and a valve having the functions of a flow rate control valve and an on-off valve. The problem to be solved is to prevent malfunction of the actuator by maintaining the isolation between the first port, the second port, and the third port even when the valve body is decreased or lost, and to improve the durability of the valve body. It is something to do.

[Means for Solving the Problems] The present invention provides first and second valve seats in the main body in a back-to-back state for communicating a first port formed in the main body with a second and third port, and A spring that biases each valve element toward each valve seat side is contracted in a back chamber defined behind the first and second valve bodies that open and close the valve seats separately, and each back chamber is connected to a second valve body. Connect to 1 port,
A piston is provided at one end of the rod of each of the valve bodies, and the piston is slidably inserted into the main body.
One of a pair of pressure chambers defined on both sides of the first piston that opens and closes the valve body is connected to the first port,
One of a pair of chambers defined on both sides of the second piston that opens and closes the second valve body is connected to the second pilot port, and the other is connected to the first pilot port that opens to the outside. 2
The above problem is solved by providing an adjustment mechanism that regulates the amount of displacement of the piston and adjusts the amount of opening of the second valve seat.

[Operation] When pilot pressure is not supplied to the first and second pilot pressure chambers, the first and second valve bodies close the first and second valve seats.

In this case, the fluid pressure of the first port is acting on the back chambers of the first and second valve bodies, and the first and second valve bodies are moved between the first and second valve bodies only by the biasing force of the spring.
Since the valve seat is closed, no excessive load is applied to the first valve body and the second valve body. Also, the first
Since the closing of the first and second valve seats by the first and second valve bodies is independent of pilot pressure, even if the pilot pressure is lost or decreased while these valve bodies are closing the valve seats, the first and second valve seats are closed. The second valve body maintains the valve seat in a closed state.

When the first pilot pressure is supplied to the first pilot pressure chamber in the above-mentioned state, the first valve body opens to the first valve seat and the pressure fluid in the second port flows into the first port. As a result, the pressure in the feedback pressure chamber communicating with the first port increases, so that the first valve body closes the first valve seat. Therefore, by setting the first pilot pressure to a predetermined pressure, the first valve seat side functions as a pressure control valve.

Next, when the second pilot pressure is supplied to the second pilot pressure chamber, the second valve body opens the second valve seat and the fluid in the first port flows out to the third port. In this case, since the second valve body abuts the adjustment mechanism,
Since the opening amount of the second valve seat is adjusted by adjusting the adjustment mechanism, the second valve seat side functions as a flow rate control valve. Further, when the second pilot pressure is discharged, the second valve body closes the second valve seat by the biasing force of the spring, so that the second valve seat side also functions as an on/off valve.

[Embodiment] FIG. 1 shows a first embodiment of the present invention, in which the control valve 2
1 main body 22 has a first port 23 and a second port 24
and a third port 25, and a first valve seat 26 that communicates with the ports 23 and 24 and a second valve seat 27 that communicates the ports 23 and 25 are formed so as to face each other. .

The first valve body 31 that opens and closes the first valve seat 26 is
The cylindrical portion is slidably inserted into the valve guide 28, and a back chamber 32 having approximately the same diameter as the first valve seat 26 formed between the first valve body 31 and the valve guide 28 is connected to the first valve guide 28.
A communication hole 33 formed in the valve body 31 communicates with the first port 23 side, and the first valve body 3 is placed in the back chamber 32.
A spring 34 that urges the valve 1 toward the first valve seat 26 is provided in a compressed manner. Therefore, the first valve body 31 has the same pressure on the first valve seat 26 side and the back chamber 32 side. A first rod 35 that slidably passes through the first valve body 31 is provided with a first piston 36 at one end and a locking shoulder 37 at the other end, and the first piston 36 is attached to a cylinder portion within the main body 22. The locking shoulder 3 is slidably inserted into the locking shoulder 3.
7 is engaged with the first valve body 31.

The feedback pressure chamber 38 defined on one side of the first piston 36 is communicated with the first port 23 through the feedback passage 39, and the feedback pressure chamber 38 defined on the other side of the first piston 36 communicates with the first port 23 through the feedback passage 39. The pilot pressure chamber 40 communicates with a first pilot port 41 that opens to the outside.

The second valve body 43 that opens and closes the second valve seat 27 is
An adapter 29 whose cylindrical portion is integrated with the main body 22
A back chamber 44 having approximately the same diameter as the second valve seat 27 formed between the second valve body 43 and the adapter 23 is bored in the second valve body 43. The spring 46 communicates with the first port 23 side through the hole 45 and compresses within the back chamber 44 to bias the second valve body 43 toward the second valve seat 27 side. Therefore, the first port 23 side and the back chamber 44 side of the second valve body 43 are at equal pressure.

A second rod 47 that slidably passes through the second valve body 43 is provided with a second piston 48 at one end and a locking shoulder 49 at the other end, and the second piston 48 is attached to the cylinder portion within the adapter 29. The locking shoulder 49 is slidably inserted and engaged with the second valve body 43.

The second pilot pressure chamber 50 formed on one side of the second piston 48 is communicated with a second pilot port 51 that opens to the outside, and the second pilot pressure chamber 50 is connected to a second pilot pressure chamber 50 formed on the other side of the second piston 48. A threaded rod 54 serving as an adjustment mechanism that adjusts the opening amount of the second valve seat 27 by contacting the second piston 48 and regulating the amount of sliding displacement thereof is screwed into the rod 52 so as to be movable in the axial direction. has been done. This threaded rod 54 can be fixed in an appropriate position with a lock nut 55.

In the control valve configured as described above, the first valve seat 26 side functions as a pressure control valve, the second valve seat 27 functions as a flow rate control valve, and they also function as an on/off valve.

That is, the first valve seat 26 is opened and closed by the pressure difference between the first pilot pressure chamber 40 and the feedback pressure chamber 38 communicating with the first port 23, so that the first pilot pressure chamber 40 is under relatively high pressure. In this case, the first piston 36 and the first rod 35 move upward while compressing the spring 34 in FIG.
Accordingly, the first valve body 31 moves upward while engaging with the locking shoulder 37 of the first rod 35, and the first valve seat 26
to open. Furthermore, when both pressure chambers 38 and 40 have the same pressure, and when the first pilot pressure chamber 40 has a relatively low pressure, the first piston 36 and the first rod 35 move downward, but the first rod 35 slides on the first valve body 31, so the first valve body 31
The closed state is maintained by the biasing force of the spring 34.
Therefore, by connecting a high pressure fluid source to the second port 24 and applying a reference pilot pressure to the first pilot port 41, fluid can be supplied from the second port 24 to the first port 23 at a controlled pressure.

Furthermore, the opening and closing of the second valve seat 27 depends on the biasing force of the spring 46 and the acting force of the second pilot pressure chamber 50, regardless of the magnitude of the fluid pressure in the first port 23 and the opening and closing of the first valve body 31. It is done by folding. That is, the second
When there is no force exerted by the fluid in the pilot pressure chamber 50, the second valve body 43 seats on the second valve seat 27 and the closed state is maintained, and conversely, the spring 46 is attached to the second pilot pressure chamber 50. If there is a force exerted by the fluid that is larger than the force, the second piston 48 and the second rod 47 move downward while compressing the spring 46 until they come into contact with the threaded rod 54, and the second valve body 43 accordingly moves downward. It moves downward to open the second valve seat 27. In this case, since the opening amount of the second valve seat 27 is adjusted by the position of the screw rod 54, the screw rod 54 is
By moving the second valve body 43 forward and backward, the opening displacement of the second valve body 43, that is, the opening amount of the second valve seat 27 is limited.
The second valve seat 27 functions as a throttle. screw rod 54
It is desirable to be able to check the advance and retreat using a scale, etc.

Therefore, even if the pilot pressure decreases or is lost while the second valve body 43 is closing the second valve seat 27, the second valve body 43 is held in the closed state by the biasing force of the spring 46. Therefore, the first port 23 and the third
This prevents the actuator from malfunctioning due to unexpected communication with the port 25. Further, the biasing force of the spring 46 may be sufficient to bring the second valve body 43 into airtight contact with the second valve seat 27.
The biasing force in the closing direction of 3 can be made small, and the second valve body 4
The durability of item 3 can be improved.

Next, the operation of the first embodiment will be explained.

Figure 1 shows the first and second pilot pressure chambers 4.
0 and 50 indicate that no pilot pressure is supplied, and the first and second valve bodies 31 and 43 close the first and second valve seats 26 and 27.

In this case, even if fluid pressure is acting on the first port 23, this fluid pressure is also acting on the back chambers 32, 44 through the communication holes 33, 45, so the valve body 3
1 and 43 are pressed against the valve seat only by the biasing forces of springs 34 and 46. Therefore, even if no pilot pressure is supplied, the valve bodies 31 and 43 will close to the valve seats 26 and 2.
7 is never released.

When the first pilot pressure is supplied to the first pilot pressure chamber 40 in this state, the first valve seat 26 side functions as a pressure control valve and an on/off valve as described above.

Further, when the second pilot pressure is supplied to the second pilot pressure chamber 50, the second valve seat 27 side functions as a flow control valve and an on/off valve as described above.

The control valve 21 of the first embodiment described above can be driven by a pilot valve assembly 60 shown in FIG. The above pilot valve assembly 60
is equipped with a port 61 connected to a high-pressure air source and ports 62 and 63 connected to the first and second pilot ports 41 and 51, and a pressure reducing valve 64 and a 3-port pilot solenoid valve are installed in the flow path between the ports 61 and 62. 65
are connected in series, and a 3-port pilot solenoid valve 66 is connected to the flow path between ports 61 and 63.

3 and 4 show a cylinder speed control circuit composed of a pressure reducing valve 71, a 3-port valve 72, a flow rate control valve 73, and a check valve 74. 21 are these valves 71,7
2, 73, and 74 are integrated, it can be used as is in their control circuits.

FIG. 5 shows a speed control circuit for a cylinder that can be stopped in the middle, which is made up of a pressure reducing valve 71, a 3-port valve 72, a flow control valve 73, a check valve 74, and an on-off valve 75. Port 3
A speed control circuit for a cylinder that can be stopped in the middle is shown, which is composed of a position switching valve 76 and a flow rate control valve 73, but the control valve 21 of the first embodiment can also be used for these control circuits.

FIG. 7 shows a second embodiment of the present invention, in which a control valve 80 of the second embodiment is slidable within the adjustment chamber 52 with a threaded rod 81 as an adjustment mechanism 53 in the adjustment chamber 52, and is connected to the second piston 48. The piston 48 also has a large diameter stopper 82, and a third pilot pressure chamber 83 is formed on the opposite side of the stopper 82 from the piston 48.
It communicates with the pilot port 84. Further, the head of the screw rod 81 screwed onto the main body 22 is located in a recess 85 formed in the stopper 82 through the through hole of the stopper 82, and by moving the screw rod 81 forward and backward in the axial direction, The stroke of the stopper 82 is regulated.

The second valve body 43 in the control valve 80 of the second embodiment opens and closes depending on the sum of the acting force of the second pilot pressure chamber 50, the acting force of the third pilot pressure chamber 83, and the biasing force of the spring 46. The third
The pilot pressure chamber 83 is the second pilot pressure chamber 5
Since the diameter is larger than 0, the acting force of the third pilot pressure chamber 83 is greater than that of the second pilot pressure chamber 50.
greater than the acting force of

Therefore, when pilot pressure is supplied to the pilot pressure chambers 50, 83, the stopper 82 and the second piston 48 move upward and downward in the figure, and the screw rod 8
By stopping at the position regulated by 1 and adjusting the screw rod 81, the second valve element 43 opens the second valve seat 27 in a throttled state. Further, when pilot pressure is supplied only to the second pilot pressure chamber 50, the second piston 48 and the stopper 82 move downward in the figure, and the second valve body 43 opens the second valve seat 27 in a fully open state.

Therefore, in the control valve 80 of the second embodiment, when the second pilot pressure is supplied to the second pilot pressure chamber 50 and the pilot is supplied to the third pilot pressure chamber 83, the second valve body 43 The valve seat 27 is opened by the opening amount regulated by the screw rod 81, and the third
When the pilot pressure in the pilot pressure chamber 83 is discharged, the second valve body 43 opens the second valve body 27 to a fully open state.

The other configurations and operations of the second embodiment are the same as those of the first embodiment, so the same reference numerals are given in the drawings and detailed explanations are omitted.

The control valve 80 of the second embodiment described above can be driven by a pilot valve assembly 87 shown in FIG. Said pilot valve assembly 87
In the pilot assembly 60 shown in FIG. 2, a port 88 connected to the third pilot port 84 is provided, and a 3-port pilot solenoid valve 89 is connected to the flow path between the port 88 and the port 61 communicating with a high-pressure air source. It is structured as follows.

FIG. 9 shows that another 3-port valve 90 is connected to the discharge port of the 3-port valve 72 in a flow path consisting of a pressure reducing valve 71 and a 3-port valve 72, and that this 3-port valve 90
One of the exhaust ports is connected to the atmosphere, and the other is connected to the flow rate control valve 73, and the exhaust gas passing through the 3-port valve 90 is switched between a state in which it is directly discharged to the atmosphere and a state in which it is discharged to the atmosphere through the flow rate control valve 73. A control circuit for two-speed control of a hydraulic actuator is shown, in which the control valve 8 of the second embodiment is shown.
0 can utilize these valves 71, 72, 73, and 90 as an integrated unit.

Note that the 3-port valve 90 can also be a closed center 3-port 3-position switching valve.

FIG. 10 shows a drive circuit for the cylinder 101 that moves the load 100 up and down by the control valve.

The drive circuit includes a signal fluid system 102 and a power fluid system 103 driven and controlled by the signal fluid system 102, and the power fluid system 103 includes first and second main control valves 104, 105, 1
The control valve 80 is used as the main control valve 104, and the control valve 21 is used as the second main control valve 105.

In the power fluid system 103, the air source is connected to the second and first ports 104 of the first main control valve 104.
The tank 107 is connected to the cylinder 1 through the first and third ports 104a, 104c of the first main control valve 104.
01 and the head chamber 101a of the second
The second and first ports 105b of the main control valve 105;
The rod chamber 10 of the cylinder 101 is connected through the rod 105a.
1b, and a third port 105c of the second main control valve 105 is open to the atmosphere.

The signal fluid system 102 also includes first and second pressure reducing valves 108 and 109 connected to the air source.
(first pressure reducing valve 108 > second pressure reducing valve 109 in output pressure) and first to fourth solenoid valves 111 to
114, and the first to third pilot ports 104d to 104f of the first main control valve 104 are connected to the first pressure reducing valve 108 and the second and third solenoid valves 1.
12, 113, and the first and second pilot ports 105d, 105e of the second main control valve 105.
The first solenoid valve 111 and the fourth solenoid valve 1
14, thereby each solenoid valve 111
~114, the main control valves 104, 105
The respective pilot pressures applied to the main control valves 104 and 105 are adjusted, and the communication state of the main flow paths in the main control valves 104 and 105 is switched.

The cylinder drive circuit with the above configuration is shown in FIG.
As shown in B, by turning on and off each solenoid 111 to 114, the cylinder is raised at high speed.
High-speed descent, intermediate deceleration up, and intermediate deceleration down are possible.

That is, since the pilot pressure reduced by the first pressure reducing valve 108 acts on the first pilot port 104d of the first main control valve 104, the first main control valve 1
04 second port 104b, first port 104a
Pressure fluid at a predetermined pressure in the tank 107 is stored through the tank 107 . When the solenoid valves 112 and 114 are turned on in this state, the first port 104a and the third port 104c of the first main control valve 104 are fully open and communicate with each other, so that the pressure fluid accumulated in the tank 107 is transferred to the head of the cylinder 101. It is supplied to the chamber 101a. In this case, when the pressure in the tank 107 decreases, the first port 1 of the first main control valve 104
Since 04a and the second port 104b communicate with each other,
The first pressure reducing valve 108 is replenished with fluid at approximately the same pressure. On the other hand, the first port 10 of the second control valve 105
5a and the third port 105c communicate with each other in a constricted state, the air in the rod chamber 101b is discharged to the atmosphere at a meter-out rate, and the cylinder 101 rises.
In this case, the first port 10 of the second main control valve 105
5a and the second port 105b are cut off because no pilot pressure is applied to them. cylinder 1
01 rises and the head chamber 101a reaches a predetermined pressure, the first port 104a of the first main control valve 104
Communication between the first port 104a and the second port 104b is cut off by the fluid pressure.

Next, when the solenoid valve 111 is turned on and the solenoid valve 114 is turned off, the first port 105a and the second port 10 of the second main control valve 105 are turned on.
5b and the third port 104 of the first main control valve 104
c communicates with the first port 104a, and the first
Since the communication between the port 105a and the third port 105c is cut off, the rod chamber 101 of the cylinder 101
The fluid in the head chamber 101a of the cylinder 101 is supplied to the tank 107, and this air is also accumulated in the tank 107. Therefore, cylinder 101 descends.

When the third solenoid valve 113 is turned on and off while the cylinder is rising and falling, the first main control valve 104 is turned on only while the third solenoid valve 113 is in the on state.
Since the first port 104a and the third port 104c communicate with each other in a throttled state, the cylinder that is ascending or descending is intermediately decelerated as shown in FIG. 11B.

It goes without saying that the above-mentioned cylinder operation can be performed by combining the respective rising and descending speeds, such as high-speed rise and intermediate deceleration downward movement, by turning on and off the solenoid valves 111 to 114.

[Effects of the invention] The present invention integrates a valve having functions of a pressure control valve and an on-off valve, and a valve having functions of a flow rate control valve and an on-off valve, in which the back chamber is communicated with the first port. At the same time, in order to press the valve body against the valve seat only by the biasing force of the spring, the control valve that drives the actuator has a simple single structure. Even if the valve seat is lost, the valve seat will not open and the actuator will not malfunction, so damage to the actuator and danger to the operator can be prevented.

Furthermore, with the above-described configuration, the biasing force of the spring acting on the valve body can be reduced compared to when the valve body is pressed by a pressure difference between opposing fluid pressures, thereby improving the durability of the valve body. be able to.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a first embodiment of the present invention, FIG. 2 is a circuit diagram of a pilot valve assembly for operating the first embodiment, and FIGS. 3 to 6 are an actuator according to the first embodiment. FIG. 7 is a longitudinal sectional front view of the second embodiment of the present invention.
Fig. 8 is a circuit configuration diagram of a pilot valve assembly for operating the second embodiment, Fig. 9 is a speed control circuit diagram of the actuator according to the second embodiment, and Fig. 10 is a circuit diagram showing the combination of the first and second embodiments. FIGS. 11A and 11B are explanatory views of the same operation as described above, and FIG. 12 is a longitudinal sectional front view of a conventional control valve. 21,80...Control valve, 22...Main body, 23,
24, 25... Port, 26, 27... Valve seat, 3
1,43...valve body, 32,44...back chamber, 35,
47... Rod, 36, 48... Piston, 3
7, 49... Locking shoulder, 38... Feedback pressure chamber, 40, 50, 83... Pilot pressure chamber,
52...Adjustment chamber, 53...Adjustment mechanism.

Claims (1)

[Claims for Utility Model Registration] First and second valve seats that communicate a first port formed in the main body with a second and third port are provided in the main body in a back-to-back state, and these valve seats are separately connected to each other. 1st to open and close
and in a back chamber defined behind the second valve body,
A spring is compressed to urge each valve element toward each valve seat, and each back chamber is communicated with the first port, and one end of the rod of each valve element is slidably inserted into the main body. one of a pair of pressure chambers defined on both sides of the first piston that opens and closes the first valve body;
The port communicates with the first pilot port, the other of which is open to the outside, and one of a pair of chambers defined on both sides of the second piston that opens and closes the second valve body communicates with the second pilot port; A control valve characterized in that the other side of the control valve is provided with an adjustment mechanism that regulates the amount of displacement of the second piston and adjusts the amount of opening of the second valve seat.